For obvious reasons it is an essential requirement that a container for the collection of urine or faeces is provided with a reliable non-return valve. Another important requirement of such containers is that they can be massproduced at a reasonable price.
It is known to use non-return valves formed by enveloping the end of the inlet tube in two foils, which are situated substantially in a plane comprising the central axis of the inlet tube end portion and which are delimited by the edges of the foils situated in a certain distance from the tube end, e.g. 2-3 cm. From the tube end the foils are joined in two diverging seams. Thereby the foils form a sort of extension of the inlet tube and do not impede the arriving liquid. When no liquid is arriving, the foils lie smoothly against each other preventing the liquid from returning, as a force would be needed for counteracting the adhesion forces between the two foils. This type of non-return valve, which in the present specification will also be termed "a foil valve", has the advantage of being mass-producable from simple materials.
In practice this foil valve has until now been manufactured in two different ways in connection with containers of the present kind. By the first method the valve and the container are produced within the same flow of work. In the inlet end of the container, the inlet tube is enveloped in two foil webs extending over the full width of the container. The edges of the foils are situated transversely to the longitudinal direction at a certain distance from the tube end. The foils are joined around the tube end and in the above-mentioned two diverging seams. Subsequently, the foils are covered with two further foils forming the outer walls of the container.
However, this construction involves the risk that the non-return valve may not be completely tight due to the occurance of windings and undulations in the valve foils when the container is filled and thereby bulging, the distance between the lateral seams of the container being shortened by the bulging, which means that the valve foils are pushed towards the central line. Under such conditions the foils will not be tight and flat, and the adhesion between the two foils will not be sufficient for preventing pockets, through which the content of the container can be forced back through the non-return valve.
It is known to avoid this by producing the foil valve separately around the tube end and by cutting away the superfluous foil material. This gives a foil valve lying freely inside the container. In this way, the valve foil will not be affected by lateral forces, e.g. when the container is bulging in filled condition, and windings or pockets do not occur in the valve and hence no leakages. Thereby, such a separately produced foil valve meets the functional requirements, but its production entails additional production costs, as first tubes provided with a valve at the tube end have to be produced, whereafter the resulting tubes can be used in the production of the container itself.
DK Patent Specification No. 135,928 discloses a container, which is flat in its empty condition, of plastic, rubber or another flexible material, which container comprises two outer walls joined to each other by a surrounding seam, and intermediate walls, said outer and intermediate walls being joined together in longitudinal seams extending in the length direction of the container and forming a number of interconnected chambers.
This known container is intended for being attached to the leg of the patient. In order to prevent splashing of the content of the container, thus avoiding embarrassing splash sounds, and in order to improve wearing comfort by reducing the forces of inertia from the liquid, i.e. to prevent movements of the liquid relative to the leg of the patient, the container is divided into mutually interconnected chambers. The container may for example consist of four layers of foil joined in seams, partly to seal the container and partly to delimit the chambers. In the known container the chambers are arranged in a row and are all bordering the outer walls, while the two intermediate foils partly form intermediate walls between the individual chambers and partly lie close to portions of the outer foils. Thus, the chambers are always limited to the outside by the two outer foils, but the outer foils are partially supplemented with one or both of the intermediate foils. This supplementing represents a waste of material, the outer foils having to be dimensioned in such a way that they by themselves are able to withstand the occurring load. In the areas having two or three layers of foils the intermediate layer or layers are not used for dividing the interior of the container into chambers, and in principle these layers could be omitted, but they have been included for productional reasons, as it is easier to produce a container, which is flat, i.e. essentially two-dimensional, in its empty condition, from four complete pieces of foil. Thus it is a drawback in the known container that the foil material included in the container is not utilized to an optimum for dividing the interior of the container into chambers, and thus a better utilization of the foil would be desirable in order to obtain more chambers by the division, each of the chambers becoming consequently smaller. The smaller the individual chambers the more the movements, if any, in the content of the container will be damped, i.e. the splashing tendency and the forces of inertia will be reduced.